I have fun developing useful software catering exactly to my individual needs, learning a GUI framework/toolkit on the side. I don't have fun needing to figure out the abstract concepts of someone else's tool, and needing to search a lot, to find a way to do something that should be very simple and very prominent in the interface, as it seems to be necessary for most decks I can find, in order to properly learn the characters including writing them.

I have not much to gain from advertising my app. It is AGPL and I don't plan on ever selling it. If it is useful to other people, that's great. If not, then it will at least be very useful to myself. I don't see what's wrong with mentioning, that I build my own, especially since this is HN. We are not on TikTok here.